(INDUSTRIAL FIELD OF THE INVENTION)
The present invention relates to a highly efficient clock.
Recently, attempts have been made to lower the current consumption of crystal clocks. In Japanese Patent Laid-Open No. 129970/1975, for example, it is disclosed that the dimensional ratio between a stator and rotor is set to a value within a predetermined range so as to lower the current consumption.
In the clock disclosed in the above-mentioned specification, the dimensional ratio of the stator and rotor is set to an optimum value. Even if an improvement has been made in this point, however, it is still impossible to obtain a sufficient efficiency, and the conversion efficiency of a conventional crystal clock motor remains at an extremely low level of 20% or less.
In additions, there has hitherto been no clock in which the drive pulse width of a motor is set from the viewpoint of high efficiency, and the drive pulse width of a motor has merely been set to a value which facilitates the production of motors and which is capable of avoiding an instable region. This point has also been a major cause which has made it impossible to improve the conversion efficiency.